1. Field of the Invention
The invention relates to an embroidery data preparing device, and particularly to an embroidery data preparing device for preparing mat-type stitch data with which a mat-type stitch pattern is formed so as to be continuous over a plurality of embroidery blocks even when the stitch terminal end portion of each embroidery block is adjacent to the stitch terminal end portion of an embroidery block which is subsequent to the embroidery block.
2. Description of Related Art
When embroidery stitch data, with which a figure, such as a one-point mark or the like, is embroidered on an article in a mat-type stitch mode using a conventional industrial embroidery-sewing machine, are prepared, outline data of the embroidery figure are first prepared and then embroidery stitch data for mat-type stitches are prepared on the basis of the outline data.
For example, the outline of an embroidery figure 30A, as shown in FIG. 19, is assumed to be divided into three embroidery blocks B1 to B3, each of which comprises a rectangular sectioned area. The block data of each of the embroidery blocks B1 to B3 are constructed by four definition end points G1-G4, G3-G6 or G5-G8. The two definition end points G1,G2 serve as stitch start end points for the embroidery block B1, and the two definition end points G3,G4 serve as stitch terminal end points for the embroidery block B1 and as stitch start end points for the embroidery block B2. Furthermore, the two definition end points G5,G6 serve as stitch terminal end points for the embroidery blocks B2,B3, and the two definition end points G7,G8 serve as stitch start end points for the embroidery block B3.
That is, in order to set the last needle location of the embroidery figure 30A to the definition end point G6, the stitch advancing direction of each of the embroidery block B1 and the embroidery block B2 is set to a direction as indicated by an arrow P. Furthermore, running stitch data are provided from the definition end point G6 to the definition end point G7, and the stitch advancing direction of the embroidery block B3 is set to a direction as indicated by an arrow Q which is opposite to the direction P. A line segment G1-G5 of the two embroidery blocks B1,B2 which will be embroidered to be continuous with each other is equi-sectioned on the basis of the density of thread to obtain plural end points g1, g2, g3, . . . , g10, and a line segment G2-G6 is also equi-sectioned on the basis of the density of thread to obtain plural end points g21, g22, g23, . . . , g30.
Likewise, plural end points g41, g42, . . . , g46 on a line segment G7-G5 and plural end points g51, g52, . . . , g56 on a line segment G8-G6 are obtained. On the basis of a mat-type stitch pitch and a displacement rate of mat-type stitches which are preset, mat-type stitch needle location data (embroidery stitch data) to obtain a prescribed mat-type stitch pattern are prepared with the end points g and the mat-type needle location points t as described above in this order: G1, t1, t2, t3, g21, t4, t5, t6, g1, t7, tS, g22, . . . , g5, t29, t30, G4, . . . , g10, . . . , t60, G6, the running stitch data (G6-G7), t201, t202, t203, g51, . . . , g46, . . . , t238, and G6. At this time, in the embroidery blocks B1 and B2, mat-type stitch needle location lines TH1-TH8 are shown (i.e., are shown as virtual lines) with neighboring needle location points, on the needle location lines, are oblique to the stitch advancing direction P at a predetermined angle. In the embroidery block B3, mat-type stitch needle location lines TH20-TH26 are likewise oblique to the stitch advancing direction Q at a predetermined angle, in this example the angle is the same in all blocks.
Accordingly, over embroidery blocks which are continuous with each other substantially in the same stitch advancing direction, the virtual lines are formed to be continuous with one another with the mat-type stitch needle location points as shown in FIG. 19. That is, a mat-type stitch pattern comprising the virtual lines is maintained over the blocks.
As described above, in order to prepare the embroidery stitch data with which the embroidery figure 30A is embroidered in the mat-type stitch mode, the outline of the embroidery figure is divided into the three embroidery blocks B1 to B3, each comprising a rectangular sectioned area, and the mat-type stitch needle location data (embroidery stitch data) to form the predetermined mat-type stitch pattern are obtained from a sewing start side for every group of the embroidery blocks (a group of B1 and B2, a group of B3) for the embroidery blocks B1,B2 whose stitch advancing directions are substantially identical to each other and the embroidery block B3 whose stitch advancing direction is opposite to the above direction. Therefore, when the end portion of the embroidery blocks B1,B2 (which belong to the first embroidery block group) is adjacent to the end portion of the embroidery block B3 (which belongs to the next embroidery block group), the mat-type stitch needle location lines TH6-TH8 of the first embroidery blocks B1,B2 and the mat-type stitch needle location lines TH23-TH26 are not continuous with each other and, thus, discontinuous at the adjacent portion of the blocks. That is, the mat-type stitch pattern is broken. Therefore, a beautiful mat-type stitch embroidery cannot be formed.